OS X: read /etc/manpaths and /etc/manpaths.d

[daenney]

Similar to /etc/paths and /etc/paths.d OS X has /etc/manpaths and /etc/manpaths.d which should be used to populate the $MANPATH environment variable.

[ridiculousfish]

Sounds reasonable

[lilyball]

OS X uses a tool /usr/libexec/path_helper to construct the default PATH and MANPATH vars. This tool only defines MANPATH if the MANPATH variable is already set. Since it's executed as the first thing in /etc/profile, which is the first file Bash sources, AFAIK the only way to actually have the MANPATH be set up is if Bash inherits a MANPATH variable from its environment.

To that end, if we do adopt this same behavior (and we don't decide to do it by invoking path_helper ourselves and parsing the output into something Fish-compatible), we should match that expectation and only set MANPATH if it's already set. The reason for this behavior is because, by leaving MANPATH un-set, man constructs its own search path based on the PATH variable.

[krader1961]

@kballard I wrote this blog article about why MANPATH doesn't work on OS X less than six months ago. I admit I did not expend much effort in figuring out why it didn't work. But I eventually gave up and added the following comment to my environ.fish file (and before that the equivalent zsh file) which is sourced from my ~/.config/fish/config.fish file:

# Setting $MANPATH is pointless on Mac OS X as it is ignored. Only
# paths in /etc/man.conf are recognized.

I would not be offended to learn that despite using OS X for over a decade I misunderstood this aspect of its behavior.

[lilyball]

@krader1961 That blog post is rather perplexing, because I just tried and it worked just fine.

> brew install coreutils
[...]
> env MANPATH=/usr/local/opt/coreutils/libexec/gnuman man -w ls
/usr/local/opt/coreutils/libexec/gnuman/man1/ls.1

If I run a Bash login shell with that MANPATH set, so as to make /usr/libexec/path_helper give me a complete MANPATH that includes the built-in stuff, then it sorts it such that man ls still gives me the built-in one, but man -a ls gives me both the built-in and the coreutils manpage.

[daenney]

I've so far never had any issues with OS X ignoring or not respecting MANPATH. Setting it is how I make sure all the man pages that get coupled with projects installed from brew show up when I do a man <thing from brew> and how I then have it generate completions for it by calling fish_update_completions.

[krader1961]

This has been resolved but wasn't automatically closed because the commit did not include the magic line "Fixes #1092".